Fuel injection system

ABSTRACT

A fuel injection system for injecting fuel into an internal combustion engine, including at least one fuel injector and a fuel rail, includes, for each fuel injector, an intake connectible to an intake section of the fuel injector. A corrugated tube is arranged between the intake of the fuel rail and the intake section of the fuel injector. The corrugated tube includes two identical end sections that are able to be brought together concentrically with guide sections of the intake section of the fuel injector and of the intake of the fuel rail. Sealing arrangement are undetachably arranged at the end sections.

FIELD OF THE INVENTION

The present invention relates to a fuel injection system for injectingfuel into an internal combustion engine.

BACKGROUND INFORMATION

A fuel injection system for supplying fuel to a mixture-compressinginternal combustion engine with external ignition as a function ofoperating characteristics is described in the German Published PatentApplication No. 28 29 057. The fuel injection system includes a metalfuel rail connected via at least one branch line to at least one fuelinjector, the branch line being configured as a metal tube and beingconnected to the fuel injector by a screw connection. A readily bendablemetal is used as branch line material. Provided between the screwconnection on the branch line and the fuel injector is a metallic,thin-walled bellows in the form of a corrugated tube bellows, by which alateral offset between the starting point of the branch line at the fuelrail and the fitting position of the fuel injector is compensated.

The fuel injection system described in German Published PatentApplication No. 28 29 057 provides that the screw connection requiresspecial forms of the corrugated tube bellows. The corrugated tubebellows may not be releasably connected to the screw connection or thefuel rail. Simple, rapid assembly of the fuel rail may be hampered.

A tube line connection in the form of a corrugated tube that is supposedto inhibit or prevent transfer of vibration is described in U.S. Pat.No. 2,014,355. The corrugated tube is surrounded on the outside by asleeve that does not touch the corrugated tube and is rigidly connectedon one end to the one tube section. On its other end, the sleeve issealed with respect to the other tube section by a flexible seal. Aflange of a retaining nut is force-fit into the corrugation arranged ineach case at the end of the corrugated tube. The corrugated tube isfastened to adjacent tube sections by the retaining nut.

Other systems include arrangements that include multiple parts and maynot permit rapid, simple assembly.

SUMMARY

The fuel injection system according to an example embodiment of thepresent invention may provide that the corrugated tube is configured asa simple, universally employable component that may be mounted byinsertion. Due to the pressure force of the sealant on a sealing line,preassembly is also possible, in which the corrugated tube according toan example embodiment of the present invention is already inserted intothe intake of the fuel rail and connected to it, together with the fuelinjectors. The corrugated tube according to an example embodiment of thepresent invention may be manufactured cost-effectively and may be usedfor a variety of different fuel injection systems.

The end sections may be enclosed radially on the outside by the guidesections, and the guide sections may include a conical entry region.

The sealing device may be made of an elastomer ring supported against asupport ring and disposed in a groove.

An elastomer ring may be secured in simple fashion by its inherenttension in a groove.

A locking plate arranged on the guide section may engage in a firstcorrugation of the corrugated tube.

Loss of the corrugated tube is thereby prevented during subsequentdisassembly.

At each end section, the first corrugation of the corrugated tube may bearranged against a grading of the intake, and, correspondingly, of theintake section.

By the guidance at the guide sections, with appropriate configuration ofthe corrugated tube, the hold-down force for the fuel injector may beexerted via the corrugated tube, since lateral sliding is prevented. Inso doing, the seal may not be stressed by the hold-down force.

Example embodiments of the present invention are illustrated insimplified fashion in the drawing and explained further in the followingdescription.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a partially cutaway view of an example embodiment ofa fuel injection system according to the present invention in the planeof a fuel injector and a corrugated tube.

FIG. 2 illustrates an example embodiment of the fuel injection systemaccording to the present invention including a locking plate, in thesame view as in FIG. 1.

DETAILED DESCRIPTION

FIG. 1 illustrates a partially cutaway view of a first exampleembodiment of a fuel injection system 1 according to the presentinvention in the plane of a fuel injector 2 and a corrugated tube 3.Corrugated tube 3, illustrated in a cutaway view, is introduced with afirst end section 4 a of two identically configured end sections 4 a, 4b into a first guide section 5 a of an intake 6 of a fuel rail. Secondend section 4 b is introduced into a second guide section 5 b formed onan intake section 9 of fuel injector 2.

Fuel injector 2 is inserted into a bore hole 7 of a cylinder head 8 ofan internal combustion engine and is illustrated in a cutaway view inthe region of intake section 9. Fuel injector 2 is sealed with respectto bore hole 7 by a sealing ring 11 made, for example, of elastomer,arranged in a groove 10.

A conical entry section 12 is formed on intake section 9. A corrugation13, initially connecting to (being next to) second end section 4 b, isarranged against a grading 14 of intake section 9. A conical entrysection 15 is also formed on intake 6. A corrugation 13, initiallyconnecting to first end section 4 a, is arranged against a grading 16 ofintake 6. Each end section 4 a, 4 b is sealed with respect tocorresponding guide is section 5 a, 5 b by a sealing ring 17 made ofelastomer. Sealing ring 17 is positioned in a groove 18 and supported bya support ring 19.

Corrugated tube 3 of fuel injection system 1 according to the presentinvention may be, e.g., identically constructed for use with fuelinjection systems 1 adapted to different installation conditions, andmay therefore be produced cost-effectively as a mass-produced part.Simple assembly by insertion is possible, corrugated tube 3 being heldagainst intake 6 or intake section 9 during subsequent assembly by thedeformation tension of sealing ring 17 with respect to guide sections 5a, 5 b. Due to its symmetrical configuration, may be impossible toinsert corrugated tube 3 the wrong way round. However, an unsymmetricalconfiguration or a fixed connection between fuel injector 2 andcorrugated tube 3, for example, by laser welding, is also possible.

By a suitably rigid configuration of corrugated tube 3, it is possiblevia gradings 14, 16 to exert a hold-down force from the fuel rail ontofuel injector 2, which holds fuel injector 2 down in bore hole 7 againstthe combustion pressure. Special hold-down devices may thereby beeliminated. Sealing of corrugated tube 3 with respect to guide sections5 a, 5 b is not adversely influenced by the hold-down tension.

FIG. 2 illustrates another example embodiment of a fuel injection system1 according to the present invention including a locking plate 20, inthe same view as the corresponding fuel injection system in FIG. 1.Corresponding components are provided with the same reference numerals.A corrugated tube 21, illustrated in a cutaway view, has a smallerdiameter compared to the corrugated tube depicted in FIG. 1. First endsection 4 a is inserted into first guide section 5 a of intake 6 of thefuel rail, and second end section 4 b is inserted into second guidesection 5 b of fuel injector 2. Each end section 4 a, 4 b is sealed bysealing ring 17, arranged in groove 18 and supported by support ring 19,with respect to corresponding guide sections 5 a, 5 b.

Fuel injector 2 is inserted in bore hole 7 of cylinder head 8 of theinternal combustion engine and is sealed by elastomer sealing ring 11disposed in groove 10.

Corrugation 13, initially connecting to respective end section 4 b, liesagainst corresponding locking plate 20.

Not only is a hold-down force transferred by locking plate 20, butrespective end sections 4 a, 4 b are also prevented from sliding out ofcorresponding guide sections 5 a, 5 b. If only one of locking plates 20is removed during disassembly, corrugated tube 21 is held with its otherend section 4 a, 4 b against the fuel rail or fuel injector 2, and maynot be lost.

1. A fuel injection system for injecting fuel into an internalcombustion engine, comprising: at least one fuel injector including anintake section; a fuel rail including an intake connectible to theintake section of the fuel injector; a corrugated tube arranged betweenthe intake and the intake section of the fuel injector and including twoend sections configured to be brought together concentrically with guidesections of the intake section of the fuel injector on one side and withguide sections of the intake on another side; and a seal arrangementundetachably arranged at the two end sections; wherein the guidesections are arranged to enclose the two end sections; and wherein theguide sections include a conical entry section.
 2. A fuel injectionsystem for injecting fuel into an internal combustion engine,comprising: at least one fuel injector including an intake section; afuel rail including an intake connectible to the intake section of thefuel injector; a corrugated tube arranged between the intake and theintake section of the fuel injector and including two end sectionsconfigured to be brought together concentrically with guide sections ofthe intake section of the fuel injector on one side and with guidesections of the intake on another side; and a seal arrangementundetachably arranged at the two end sections; wherein the sealarrangement includes an elastomer ring arranged in a groove.
 3. The fuelinjection system of claim 2, wherein the guide sections are arranged toenclose the two end sections.
 4. The fuel injection system of claim 2,further comprising: a supporting ring arranged to support the elastomerring.
 5. A fuel injection system for injecting fuel into an internalcombustion engine, comprising: at least one fuel injector including anintake section; a fuel rail including an intake connectible to theintake section of the fuel injector; a corrugated tube arranged betweenthe intake and the intake section of the fuel injector and including twoend sections configured to be brought together concentrically with guidesections of the intake section of the fuel injector on one side and withguide sections of the intake on another side; and a seal arrangementundetachably arranged at the two end sections; wherein the sealarrangement includes an elastomer glued to the two end sections.
 6. Thefuel injection system for injecting fuel into an internal combustionengine, comprising: at least one fuel injector including an intakesection; a fuel rail including an intake connectible to the intakesection of the fuel injector; a corrugated tube arranged between theintake and the intake section of the fuel injector and including two endsections configured to be brought together concentrically with guidesections of the intake section of the fuel injector on one side and withguide sections of the intake on another side; a seal arrangementundetachably arranged at the two end sections; and a locking platearranged on each of the guide sections and engaged in a firstcorrugation of the corrugated tube.
 7. A fuel injection system forinjecting fuel into an internal combustion engine, comprising: at leastone fuel injector including an intake section; a fuel rail including anintake connectible to the intake section of the fuel injector; acorrugated tube arranged between the intake and the intake section ofthe fuel injector and including two end sections configured to bebrought together concentrically with guide sections of the intakesection of the fuel injector on one side and with guide sections of theintake on another side; and a seal arrangement undetachably arranged atthe two end sections; wherein at each of the two end sections, a firstcorrugation of the corrugated tube is arranged against a grading of theintake and of the intake section.
 8. The fuel injection system of claim5, wherein the guide sections are arranged to enclose the two endsections.
 9. The fuel injection system of claim 6, wherein the guidesections are arranged to enclose the two end sections.
 10. The fuelinjection system of claim 7, wherein the guide sections are arranged toenclose the two end sections.